|Your BIOS can be downloaded from Asus' website by finding your exact model (usually Support>Downloads then find your model and look on the list for your BIOS on the list).|
I recommend testing your memory before testing the hard drive since a bad memory segment can give you a false reading on your hard drive test as well as other problems. Test your memory with Memtest86 which you download as an ISO image and burn a bootable CD. Then you make sure that your CD/DVD drive is first in your boot order (in your BIOS), then restart the machine (sometimes you need to 'hit any key to boot from CD/DVD') and let memtest run through all tests. Any error is not acceptable. If there is any errors, retest with one stick at a time to find bad one.
To test your hard drive you need to download your hard drive manufacturer's utility from their website (or just use Seatools from Seagate since it is universal) and burn a bootable CD (as above), boot to it and run their Long Test. The utility can repair minor segment problems, but if there are too many or if there is a more serious problem replace it.
If the memory and hard drive tests OK, back up all of your personal files, make sure you have all of your program install disks for programs you added, and begin a Factory Restore. This may be as easy to start as tapping a key or two on start up, but check your manual online for the exact details. This will return your hard drive to the same as it was wen they shipped it out. You will need to redo all Windows updates, reinstall your antivirus program and other programs you added, remove junk programs Asus included that you do not use, set up your personal settings and add back your personal files, just as if it was a brand new computer.
You have to be a little bit crazy to keep you from going insane.